THERE ARE already so many bad things in the Senate GOP tax bill, what’s one more? Well, ask the polar bears. On Tuesday, Republicans on the Senate Budget Committee added to their already malformed tax legislation a provision that would open the Arctic National Wildlife Refuge to oil and natural gas drilling. This is a poor idea that senators should resist sneaking into law while most of Washington is preoccupied with a major tax overhaul.

We do not oppose offshore drilling everywhere. The policy then-President Barack Obama established shortly before leaving office was too strict. It would be defensible for President Trump to loosen restrictions on offshore drilling along the Atlantic Coast and to maintain open waters in the Gulf of Mexico. As long as the United States demands oil and does not slake some of its appetite from domestic production, even more drilling will occur in places with environmental standards that are more lax.

But that principle does not justify drilling everywhere there is a drop of recoverable oil. The Arctic National Wildlife Refuge deserves special protection. Known as “America’s Serengeti,” it is one of the last pristine wildernesses in the world, an expanse of rivers, permafrost and ocean-side habitat that teems with life. Caribou, polar bears and musk oxen depend on this untouched land. Birds migrate to the refuge from all over the world. Whales live just offshore. This zone is off-limits to development.

For generations, Alaskan members of Congress generally have wanted to exploit what may be significant deposits of oil and gas beneath a coastal plain in the refuge, while environmentalists have fought to preserve it undisturbed. Today proponents insist that new technologies would enable drillers to reach oil with a minimal footprint. Yet successfully exploiting the refuge’s dispersed resources would likely require many wells distributed across the coastal plain, linked by pipelines and serviced by gravel mines and other infrastructure. The warming climate would over time make ice-based travel less useful, calling for more traditional gravel road building. Oil development is simply incompatible with what should be the purpose of the refuge — preserving a unique environmental marvel.

When some in Congress previously tried to open the refuge, a broad group of lawmakers killed the plans. If this issue were taken up on its own, drilling would struggle to attract the 60 votes it would need to overcome a Senate filibuster. But if the proposal remains in the Senate tax legislation, it would be just one small piece of a giant bill — a bill that requires only 51 votes to pass. Senators who defended the refuge in the past must insist on removing it — or, better yet, simply vote against the whole unworthy package.